Monopulse principles and techniques / Samuel M. Sherman.

Format:

Book

Author/Creator:

Sherman, Samuel M.

Language:

English

Subjects (All):

Monopulse radar.

Physical Description:

xviii, 363 pages : illustrations ; 24 cm

Place of Publication:

Dedham, MA : Artech House, [1984?]

Summary:

+ d and

- d||p176

Contents:

1.1 Review of Radar Principles 1

1.2 Tracking Radars and the Evolution of Monopulse 3

1.3 A "Baseline" Monopulse Radar 8

1.4 Advantages and Disadvantages of Monopulse 17

1.5 Non-Radar Uses of Monopulse 19

2. Terminology, Definitions, and Notation 23

2.1 The Meaning of Monopulse 24

2.2 Apertures and Illumination Functions 27

2.3 Patterns, Lobes, and Beams 28

2.4 Sum and Difference Patterns 29

2.5 Sum and Difference Notation 32

2.6 "Error" Signals 32

2.7 Complex Signal Representation and Complex Envelopes 33

2.8 Elevation, Azimuth, and Traverse 38

3. The Monopulse Output as a Complex Ratio 47

3.1 General Principles 47

3.2 Relative Phase of Difference and Sum 49

3.3 Some Useful Relationships and Formulas 50

4. Components Used in Monopulse 53

4.1 Antenna Mounts 53

4.2 Antennas 55

4.2.1 Lens Antennas 57

4.2.2 Single-Reflector Antennas 58

4.2.3 Cassegrain (Double-Reflector) Antennas 60

4.3 Feeds 62

4.4 Devices for Forming Sums and Differences 66

4.4.1 Hybrid Junctions 67

Magic-T Junction 67

Hybrid Ring ("Rat-Race") Junction 69

4.4.2 Directional Couplers 70

4.4.3 Comparators 73

4.4.4 Other Methods of Obtaining Monopulse Sum (or Reference) and Differences 75

4.4.5 Graphical Symbols 77

4.4.6 Proof of Quadrature Phase Relationships in Directional Couplers 80

4.5 Receivers 84

5. Amplitude-Comparison and Phase-Comparison Classification 89

5.1 Descriptions 91

5.2 Phase Fronts, Phase Centers, and Related Concepts 94

5.2.1 Transmitting Antennas 95

5.2.2 Receiving Antennas 98

5.2.3 Targets 98

5.2.4 An Example: Phase Fronts of a Two-Element Source 99

5.2.5 Simplification at Large Distances 101

5.2.6 Phase Centers of Array Antennas 103

5.2.7 Phase Centers of Reflector Antennas 106

5.3 Definitions and Further Discussion 107

5.4 Distinction Based on Relative Phase of Sum and Difference 108

5.5 Distinction Based on Relative Phase of Illumination Functions 112

5.6 Distinction Based on Sum and Difference Patterns 113

5.7 Apparent Conversion of One Class to the Other 114

5.8 Distinction Based on Other Criteria 116

5.9 Application to Array Antennas 117

5.10 An Example of Theoretical Equivalence 118

5.11 Summary of Amplitude-Comparison and Phase-Comparison Classification 124

6. Optimum Feeds for Amplitude-Comparison Monopulse 129

6.1 Nature of Optimization 129

6.2 f/D Ratio 131

6.3 Effect of Squint Angle in a Four-Horn Feed 132

6.4 Optimization of Squint Angle 135

6.5 Comparison With Measured Patterns 137

6.6 Beacon Operation 140

6.7 Comparison of Beam Squint Angle and Feed Offset Angle 141

6.8 Effect of Squint Angle on Normalized Difference Pattern 141

6.9 Other Feed Configurations 143

6.10 Summary of Feed Optimization 146

7. Monopulse Processors 151

7.1 Functions and Properties of Monopulse Processors 152

7.2 Range Gating 155

7.3 Angular Coordinates for Monopulse Calibration 156

7.4 Exact Monopulse Processor 157

7.5 Processor Using Phases and Linear Amplitudes of s and d 159

7.6 Processor Using I and Q 161

7.7 Processor Using Phases and Logarithmic Amplitudes of s and d 163

7.8 Processor Using "Dot-Product" Detector with AGC 165

7.9 An Approximate "Dot-Product" Detector 168

7.10 Noncoherent Processor Using Sum and Difference of |[upsilon][subscript 1]| and |[upsilon][subscript 2]| 172

7.11 Processor Using

7.12 Processor Using log |[upsilon][subscript 1]| and log |[upsilon][subscript 2]| 177

7.13 Processor Using s [plus or minus] jd 181

7.14 Two-Channel Monopulse Using s + d and s - d 186

7.15 Phase-Amplitude Monopulse 190

7.16 Single-Channel Monopulse 192

7.17 Conopulse 194

7.18 Summary of Monopulse Processors 196

8. Response to Unresolved Targets 201

8.1 Review of Monopulse Response to a Point Target 204

8.2 The Meaning of Unresolved Targets 205

8.3 Superposition as an Approximation 206

8.4 The Two-Target Problem 207

8.5 The Complex Indicated Angle 210

8.6 Physical Interpretation 215

8.7 Measurement of the Imaginary Part (Quadrature-Phase Component) 216

8.8 Effect of Local-Oscillator Frequency 218

8.9 Detection of Presence of Unresolved Targets 218

8.10 Mean and Variance of Indicated Angle 219

8.11 Weighted Mean of Indicated Angle 223

8.12 Possibility of Determining Angles of Unresolved Targets 224

8.13 Information Derivable From Real Part 231

8.14 Removal of Initial Assumptions 232

8.15 Extensions of Monopulse Techniques and Fundamental Limitations 234

8.16 Closed-Loop Tracking 236

8.17 More Than Two Targets 237

8.18 Non-Independent Targets 238

9 Multipath 243

9.1 Flat-Earth Specular Multipath Model 245

9.2 Effect on Detection 248

9.3 Effect on Closed-Loop Elevation Tracking 249

9.4 Types of Multipath Remedies 254

9.5 Beam Pattern Design 254

9.6 Range or Doppler Resolution 255

9.7 Smoothing and Averaging 259

9.8 "Low-E" Modes 259

9.9 Offset-Null Tracking 262

9.10 Elevation Patterns Having a Symmetrical Ratio 263

9.11 Double-Null Tracker 267

9.12 Use of the Complex Indicated Angle 269

9.13 Independent-Target Methods 278

10 Monopulse in Array Antennas 283

10.1 Principles of Operation 283

10.2 Array Coordinates 285

10.3 Arrays With Space Feeds 286

10.4 Arrays With Constrained Feeds 288

10.5 Classification as Amplitude-Comparison or Phase-Comparison 291

10.6 Special Types of Arrays 294

11. Error Due to Noise 297

11.1 A Useful Approximate Formula 298

11.2 Analytical Model of Noise Error 299

11.3 Bias in Monopulse Ratio 302

11.4 Exact Solution for Probability Density Function of d/s 305

11.5 First-Order Approximation to Standard Deviation of d/s 307

11.6 Higher-Order Approximation to Standard Deviation of d/s 311

11.7 Conversion From Monopulse-Ratio Error to Angle Error 313

11.8 Effects of Other Conditions 316

11.8.1 "Inexact" Monopulse Processors 316

11.8.2 Closed-Loop versus Open-Loop Operation 317

11.8.3 Multiple-Pulse Estimates 317

11.8.4 Fluctuating Targets 318

11.9 Summary of Formulas and Practical Considerations 322

12 Special Topics 329

12.1 Difference and Sum Patterns Having a Ratio Proportional to Angle 329

12.1.1 General Properties 329

12.1.2 Applications and Implementation 330

12.1.3 Derivation of Equations 331

12.1.4 Characteristics of the Patterns and Illumination Functions 332

12.1.5 Computation of Patterns at Indeterminate Points 335

12.1.6 Other Pattern Pairs Having a Constant Monopulse Slope 336

12.1.7 Extension to Electronically Steerable Arrays 338

12.2 The Diagonal Difference Signal 339

12.3 Units of Angle and Sine Space 343

12.4 Comparison With Rhodes' Terminology and Classification 345.

Notes:

Includes bibliographical references and index.

ISBN:

0890061378

OCLC:

10989644